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Portal:Biology

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Introduction

A panoramic view from a ridge located between Segla and Hesten mountain summits in the island of Senja, Troms, Norway in 2014
A panoramic view from a ridge located between Segla and Hesten mountain summits in the island of Senja, Troms, Norway in 2014

Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of at least one cell that processes hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments.

Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations. Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the scientific method to make observations, pose questions, generate hypotheses, perform experiments, and form conclusions about the world around them.

Life on Earth, which emerged more than 3.7 billion years ago, is immensely diverse. Biologists have sought to study and classify the various forms of life, from prokaryotic organisms such as archaea and bacteria to eukaryotic organisms such as protists, fungi, plants, and animals. These various organisms contribute to the biodiversity of an ecosystem, where they play specialized roles in the cycling of nutrients and energy through their biophysical environment. (Full article...)

A mule is a sterile hybrid of a male donkey and a female horse. Mules are smaller than horses but stronger than donkeys, making them useful as pack animals.

In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are.

Species are reproductively isolated by strong barriers to hybridization, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled. (Full article...)

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Fruit of the Horse Chestnut tree. The dried seeds are often used in the English children's game: Conker.

Major topics

History History of biology | timeline of biology and organic chemistry | history of ecology | history of evolutionary thought | history of geology | history of model organisms | history of molecular biology | history of paleontology
Overview Biology | science | life | properties (adaptationenergy processinggrowthorderregulationreproduction, and response to environment) | hierarchy of life (atommoleculeorganellecelltissueorganorgan systemorganismpopulationcommunityecosystembiosphere) | reductionistic | emergent property | mechanistic | scientific method | theory | law | peer review | biology journals
Chemical basis Matter | elements | compounds | atoms | molecules | chemical bonds | carbon | organic compounds | macromolecules | carbohydrate | protein | protein structure | protein folding | lipid | DNA | RNA
Cells Prokaryote | eukaryote | cell wall | cell membrane | cytoskeleton | mitochondrion | chloroplast | nucleus | endoplasmic reticulum | Golgi apparatus | cell cycle | mitosis | metabolism | cell signaling | protein targeting | metabolism | enzyme | glycolysis | citric acid cycle | electron transport chain | oxidative phosphorylation |photosynthesis |meiosis  | mitosis
Genetics (Intro) Classical genetics | mendelian inheritance | gene | phenotype | genotype | ploidy | alternation of generations | molecular genetics | gene expression | gene regulation | genome | karyotype | DNA replication | transcription | translation | recombination | chromosome | epigenetics | splicing | mutation | genetic fingerprint | chromatin | ecological genetics | population genetics | quantitative genetics
Evolution (Intro)  | omne vivum ex ovo | Natural selection | genetic drift | sexual selection | speciation | mutation | gene flow | evolution of sex | biogeography | cladistics | species | extinction | tree of life | phylogenies | three-domain system
Diversity Bacteria | archaea | plants | angiosperms | fungi | protists | Animals | deuterostome | insects | molluscs | nematodes | parasitism | Primate | mammal | vertebrate | craniata | chordate | viruses
Plant form and function Epidermis | flower | ground tissue  | leaf | phloem | plant stem | root | shoot | vascular plant | vascular tissue | xylem
Animal form and function Tissues | fertilization | embryogenesis | gastrulation | neurulation | organogenesis | differentiation | morphogenesis | metamorphosis | ontogeny  | Development | senescence  | reproduction | oogenesis | spermatogenesis
Ecology Ecosystem | biomass | food chain | indicator species | habitat | species distribution | Gaia theory | metapopulation  | life cycle | Life history | altricial - precocial | sex ratio | altruism | cooperation - foraging | learning | parental care | sexual conflict | territoriality | biosphere | climate change | conservation | biodiversity | nature reserve | edge effect | allee effect | corridor | fragmentation | pollution | invasive species | in situ - ex situ | seedbank
Research methods Laboratory techniques | Genetic engineering | transformation | gel electrophoresis | chromatography | centrifugation | cell culture | DNA sequencing | DNA microarray | green fluorescent protein | vector | enzyme assay | protein purification | Western blot | Northern blot | Southern blot | restriction enzyme | polymerase chain reaction | two-hybrid screening | in vivo - in vitro - in silico | Field techniques | Belt transect | mark and recapture | species discovery curve
Branches Anatomy | biotechnology | botany | cell biology | ecology | evolutionary biology | genetics | marine biology | microbiology | molecular biology | mycology | neuroscience | paleontology | phycology | physiology | protistology | virology | zoology
Awards Nobel Prize in Physiology or Medicine
See also Template:History of biology

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Morgan in 1891

Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity.

Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University's Schermerhorn Hall, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. (Full article...)

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